A lot of the confusion stems from the fact that not everyone agrees on definitions for values, morals, and ethics. The key distinction between ethics and morals is that ethics are imposed by an external source, often the authority of government. The "perceived" morality is definitely ethics, and it shapes individuals' values.

There are certainly traces of Kohlberg's universal ethics in every society, but he's mostly referring to a generally moral progression that individuals and societies make.

While people may agree on moral principles in writing, in practice our actual ethics/values do not necessarily align. Hope that cleared things up for you.

An objective standard for morality doesn't entail that everyone must believe in it, or even be aware of this objective standard.

Human perception of morality varies wildly based on time, place, situation, and who you ask.

Regardless, we see objective trends that all societies seem to share morally -- for example, the nonaggression principle. HumanRightsAction.org published a practical code of ethics, which the vast majority of people would agree on (independent of society or time): http://www.humanrightsaction.org/ethics/english.html

Even the fact that societies are ethically progressing in a particular direction requires a sense of objectivity, or objective moral direction that we are guided by.

A lot of other commenters here are seeming to point toward consequentialism, or utilitarianism, as the objective standard, but I want to point out that an objective morality can just as easily be deontological in nature.

Our social progression seems to indicate that this deontological standard is respecting the rights of others. For example, Kant's categorical imperative: "Act only according to that maxim whereby you can, at the same time, will that it should become a universal law."

Therefore, objective morality cannot work in the real world.

A couple of things about this point:

1) Even if objective morality were not pragmatic, this does not make it nonexistent or false.

2) Regardless, an objective sense of morality is surely more functional than moral relativism. Without an objective standard, we cannot judge the morality of actions at all.

Human morality often reflects evolution... It's probable, therefore, that a different civilization evolved in different conditions would not follow our objective morality.

Even if evolution were the guiding force, this would still be an objective morality. Under different conditions, ensuring the well-being of a population as a whole requires the same principles (we should not kill, lie, etc.). I'm not claiming that this the origin of morality -- just addressing your point.

To explain your argument with your friend about cannibalism, I would argue that cannibalism is not necessarily categorically wrong -- it depends on intent, which ties into the objective deontological ethics I mentioned earlier.

I think it's a stretch to describe this as a scientific issue, when it's clearly a question of whether something exists -- philosophical. Science relies on empiricism, and what you're describing really isn't empirical at all.